The present invention relates to compositions of matter containing tin(II) dihydrocarbylphosphorodithioates and methods of preparing same.
In the catalytic cracking of hydrocarbons, contaminants contained within the feedstock, for example, nickel, vanadium, and iron, become deposited on the cracking catalyst and decrease the ability of the cracking catalyst to crack the feed into lower boiling hydrocarbons, for example, gasoline. The adverse effects of metallic contaminants on the cracking catalyst can be at least partially overcome by treating the catalyst with agents which reduce the ability of the contaminants on the catalyst to adversely affect the cracking process. The treatment of the cracking catalyst is most conveniently accomplished by incorporating the selected treating agent or agents into the feedstock to be cracked.
Treating agents to be employed in combination with the feedstock to the cracking process are desirably oil-soluble so that they can be suitably diluted, for ease of handling and metering into the hydrocarbon feedstock, with a diluent which is not incompatible with the cracking process. It is also desirable that the treating agent be rich in components that are highly effective for negating the effects of metals deposits on the cracking catalyst, so that only small amounts of the treating agent need be incorporated into the feedstock, thus minimizing outlay for the necessary equipment and the amount of treating agent present in the cracking zone. It is still further highly desirable that the treating agent be chemically stable, and homogeneous, so that it enjoys a long shelf-life without significant phase separation or decomposition. It is also highly desirable that the treating agent be free of components which can cause erosion in process equipment, that it be relatively non-toxic, that it be simple and inexpensive to manufacture from readily available materials, and that it be chemically compatible with certain other treating agents frequently employed in catalytic cracking processes.